The invention relates generally to thermal measurement systems, and more particularly to a multiwavelength thermometer.
Current approaches to measuring temperatures of the actual components in high temperature and/or high pressure environments have drawbacks.
One approach to monitoring hot component temperatures is to indirectly measure the temperature of the gas leaving an engine and to use this as an indication of the component temperature. However, indirect temperature measurement techniques are relatively inaccurate, and approaches for measuring component temperatures directly have been proposed.
Another approach to measuring absolute temperatures of component parts is through the use of thermocouples. Temperature measurement in these types of harsh environments, however, is limited due to uncertain radiation loss and the short lifetime of thermocouples due to their intrusiveness into the actual component and/or gas environment. Additionally, these intrusive measurement methods only provide temperature information at a single point, which is of limited use for operations such as gas turbine operations.
Pyrometers, also referred to as infrared thermometers, provide non-contact temperature measurements of an object and have been used to estimate temperatures of objects in a variety of industrial, scientific, and commercial processes. One of the techniques in pyrometry that has been used is multi-wavelength pyrometry. In this technique, absolute temperature of an object is determined by sampling and combining radiation emitted by the object at multiple wavelengths.
Another technique for measuring temperature in this type of environment is to use lasers. While lasers may offer the benefit of accuracy, they too suffer from their own shortcomings, namely high cost, increased sensitivity, and a continual need for retuning. Additionally, none of these techniques are able to simultaneously measure temperatures of the gaseous environments that these components often reside in.
Another complicating factor for measuring temperatures in certain harsh environments is that in certain combustion regions (e.g., aircraft engines) adding devices of any sort in the combustion region is highly regulated. For example, the FAA restricts what devices, parts, and the like may be located with the turbine region. So, while passive measurement of temperature may be more desirable in addressing the regulatory restrictions, it has limitations technically.
Therefore, there is an ongoing need for improvements in temperature measurement, especially in harsh environments.